


Ghosts in the Machines

by KennaM



Category: Big Hero 6 (2014), Generator Rex
Genre: Amnesiac Tadashi, Crossover, Gen, Nanites, Post-Movie(s), Robotics, Season/Series 03, Shared Universe, Tadashi Lives
Language: English
Status: In-Progress
Published: 2016-05-30
Updated: 2016-07-12
Packaged: 2018-07-11 02:48:18
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 5
Words: 9,251
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/7024210
Author URL: https://archiveofourown.org/users/KennaM/pseuds/KennaM
Summary: <blockquote class="userstuff">
              <p>Hiro Hamada isn't prepared for his tech to get stolen, <i>again</i>. He certainly isn't prepared to see it used to subjugate EVOs and force them under Providence control. Caesar says he has a plan, to save the world no less, but Rex no longer knows if he can trust his own brother.</p><p>Meanwhile the EVOs of San Fransokyo are preparing for a fight to protect their very lives, led by a mechanical EVO whose small machine swarm, and burn-scarred face, look very familiar.</p><p>(*Indefinite Hiatus*)(Sequel to Professional Bot Fighters, but you don't have to read that one first.)</p>
            </blockquote>





	1. Chapter 1

**Author's Note:**

> I said I wasn't going to write an alive!Tadashi fic, and here I am writing an alive!Tadashi fic.
> 
> This fic follows a few months after the events of Professional Bot Fighters, but nothing really heavily plot-relevant carries over into this story (and what does carry over with be explained in narration).

Hiro heard about the EVO collars on the news, and cycled through feelings of awe, recognition, confusion, and anger. They flashed the image of the updated collar prototypes and Hiro recognized the design instantly. It looked a bit off, something wrong or misplaced, so he paused the TV just to make sure, studied the blurry image then searched through the patent designs online, and cursed loudly.

That was _Hiro’s_ design. It was radically altered but Hiro had stared at his project prototypes for months, put all his hopes and dreams for the future on those designs. He’d dropped the project after the fire, almost for good, and had the tech stolen out from under him. _Twice_.

Hiro seethed. He pulled Rex’s number up on his phone and called on the spot. The line didn’t connect and Hiro threw the phone across the room, scaring the small litter of kittens Mochi had surprised them all with. With a growl of frustration Hiro retrieved the phone, and tried calling the number two more times. He cursed again when it still wouldn’t connect.

He had to dig through Aunt Cass’ purse to find the business card with Doctor Holiday’s number, but finally Hiro got a dial tone. The scientist picked up after four rings. “Hiro Hamada?” she said into the phone.

“What the _hell_ is going on at Providence?” he asked without any greeting.

He could hear a sigh on the other end of the line, and Holiday said, “A lot.”

Hiro bristled. “What kind of answer is that?”

“An honest one. What’s wrong?”

Hiro swung around in his desk chair, stared at the empty bed on the other side of the room, and forced himself to take a breath. Whatever was going on, it wasn’t Holiday’s fault – she’d never had access to his tech. “So Providence is controlling wild EVOs now?” he tried to ask calmly.

“That seems to be the case,” Holiday said. Her answer just irked him even more, but she continued. “I’m not happy about it either, Hiro, but – why are you calling me?”

“That’s _my_ tech,” Hiro spat.

“What?”

“I looked at the patent designs. That’s my nanobot tech. The only people who ever saw my designs were my friends, and my brother, and Rex’s brother Caesar.”

“Oh. Shit. Hiro.”

“He still works for you guys, right? Caesar. I need to talk to him. I need to….” Hiro’s voice trailed off. He wasn’t sure what he wanted to say. Images of Callaghan flashed through his mind, his nanobots loose through the city and out of his control. Using that same tech to control actual living beings though? That was on a whole different level. Hiro couldn’t even guess what might happen, or how he might stop it. He’d be responsible if he didn’t/

“I need to talk to Rex,” Hiro finally said. They were friends, sort of. Rex could get through to Caesar for him. “Where is he?”

Doctor Holiday was silent for a moment longer than Hiro was comfortable with. He could hear what he thought was running water in the background. “Hiro,” Holiday finally said, “Rex is gone.”

Hiro’s throat went dry. “Gone?”

“Missing. He disappeared, a month ago. Providence is keeping a tight lid on it, but… things have changed.” For the first time, Hiro noticed how weary Holiday sounded. “It’s bad. There are new people in charge, and they’ve lost their cure, and they’re not even looking. They’re not looking for _Rex_. These collars are supposed to be their new solution, but….”

Hiro waited a moment, and asked, “Holiday?”

“Hiro, I don’t work for Providence anymore.”

Rex missing. Providence under new management. Control collars using stolen tech. Hiro swallowed thickly. “What the _hell_ is going on at Providence?”

* * *

Obake heard about the EVO collars through word of mouth. A couple of kids stumbled into the shelter one night and told everyone gathered that they were heading north to escape Providence.

“That seems a bit extreme,” one man said with a chuckle. His voice was gravely and rough through his mutation. A couple of the others laughed, but Okabe looked up from his bedroll in the corner. His machines clicked quietly with unease.

“You haven’t seen what we’ve seen,” one of the kids said, a girl with limbs like spiders and eyes too large for her head. She glanced at her companion and her expression was undecipherable on her deformed face. “They’re not just capturing EVOs anymore. They’re… leashing us. Controlling us.”

Obake’s fingers stilled over the edges of his book but his machines bristled, clacking against each other. A few dropped from the swarm that surrounded his body and skittered across the concrete floor before being drawn back up to the mass. The shelter regulars ignored the noise but the two kids glanced over at him, and their eyes met. “What do you mean, ‘leashing’?” Obake asked.

The spidery girl swallowed. “They’ve got control collars,” she said. “They put one on and zap you, and they can make you do whatever they want.”

A few of the residents began murmuring. “That’s nothing new,” a woman said. She was small, and her skin was green and veined like leaves. She didn’t sound entirely sure of herself. “Right? They used collars for training on wild EVOs.”

“This is different,” the other kid spoke for the first time. Obake couldn’t distinguish a gender under all that fur. “They’re not just collaring wild EVOs, they’re collaring everybody. All EVOs are being targeted. None of us are safe.”

The room got louder as more EVOs whispered to each other, everyone who’d laughed suddenly realizing this wasn’t a joke. Obake dropped his book onto his pillow and his machines rolled down his arms automatically, covering his burnt and scarred hands until none of the skin showed, and he looked like some sort of metallic animal. More than one EVO in the room was looking his way.

“What do we do, Obake?” someone asked. He wasn’t sure who.

“I don’t know,” Obake admitted.

“We’re running,” the furry kid said. “As far north as we can. Providence may be everywhere, but they can’t find us if we stay out of populated areas.

“But _we_ can’t run,” Obake said, looking around the room. The machines covering his body drew tighter together, protectively, making him appear to shrink in size. “This is our home.”

He honestly wasn’t sure if that was true.

“We won’t let them take us,” another voice spoke up. The man, unbelievably large, and deformed to look like a bull, glanced over at Obake. They both nodded. They weren’t the oldest at the shelter, probably, but they were the strongest, and Obake had only been around a few months but everyone knew he was practically a genius.

Obake’s machines, responding instantly to his thoughts, shifted around him, and he took on a more menacing form. “Providence won’t have us,” he said.


	2. Chapter 2

Obake had just returned from his morning food run when the EVO shelter door slammed open. His arms were crossed tight across his chest, his machines peeling cans open at the shelter’s single countertop, and he didn’t turn to see who’d entered until he heard someone call out his name.

“Obake!” It was Stripe, a regular at the shelter, a kid Obake knew well. The kid was only about ten years old, and his mutation had left him almost normal-looking, besides the dark tiger stripes down his body, and the row of pointed teeth. Obake turned to see him, nearly doubled over in the doorway to catch his breath. This could mean nothing good.

“What’s wrong?” Obake asked. His voice barely carried over the length of the room.

“Providence,” Stripe said, huffing. “They’re in the city. They’re chasing Brick.”

Providence was finally making their move, Obake thought. Brick was Stripe’s best friend, just another little kid whose nanites went haywire. His life was already a mess and Providence just wanted to make it worse.

Obake took a step towards the door and his machines followed, tumbling off the countertop and covering him in a layer of cold metal. They massed at his feet, lifting him a few inches off the ground. He braced his knees and in a single instant the machines had carried him to the shelter door.

“Where?” Obake asked. Stripe jumped out of the way, and pointed.

“They gotta be almost at Market Street by now,” he called to Obake’s retreating back.

Obake flew through the city streets with ease. His machines made him faster than any other EVO he knew, and his appearance, a hulking metallic beast charging down the sidewalk, meant everyone else immediately moved out of his way.

EVOs were common enough in a large city like this that many people were used to seeing them. The normal people in Obake’s neighborhood knew about the EVO shelter, didn’t seem to mind their comings and goings, gave them work to do and food to buy.

Travel too far from home base, however, and it was a different story. As Obake raced down the streets, following the signs of a struggle, and the sight of Providence jets hovering above the city, the people he passed grew more and more afraid of him. They weren’t used to seeing anything but the mindless monsters they showed on the news, Obake knew.

It didn’t help that there was already a battle raging nearby. He passed people running from the scene, civilians who hung back to take pictures or just witness what happened. Obake was close enough now he could hear the sound of Providence weaponry. He moved up behind a white unmarked Providence van and peered around the side of it, trying to get a feel for how things were going, where Brick was, and how to get the kid out of the fight.

Obake spotted Brick huddling behind a bus stop structure, trying to make his rocky form as small as possible. At his side, watching around the corner of the structure, was a woman in a pink dress. Above them was a blue mini-kaiju EVO providing literal cover fire.

Big Hero 6.

Obake knew about the San Fransokyo superhero team just as well as anyone. They saved people from burning buildings and runaway tram cars, they stopped gang wars before they happened, and even took on a real-life supervillain a few months back. They proved their capabilities at least once a week. And now it seemed like they were helping EVOs.

It made sense. They had an EVO on their team, after all, even if no one knew anything about the Blue Kaiju. He’d never shown up in the EVO underground, and with those unblinking eyes Obake suspected he wasn’t even a real EVO after all.

The Red hero, a huge robot with retractable wings, zipped by overhead, drawing fire from the Providence jets. The Pink hero was still standing by Brick, lobbing chemical bombs at the Providence agents on the ground. They were joined moments later by the Purple hero, a small kid about Brick’s own age. Obake watched as the two of them talked, looking around for an escape route.

The Heroes had this all under control, Obake thought to himself. Even as he watched the remaining Providence forces were getting pushed back, and they seemed to realize the task was pointless. The Green hero slashed their guns in half, the Yellow hero knocked down anyone who refused to retreat. The whole thing would be over in minutes.

The machines holding Obake up from the ground slowly swarmed up over his body, dropping the soles of his shoes to the pavement. As each machine linked together, his senses lit up. The subtle warmth of the sun intensified, and the sounds of the battle rang clearer. He could almost hear what Brick and the Purple hero were saying to each other.

He heard when Brick stood up though, preparing to run. His pace was painfully slow but the Purple hero ran beside him, both of them heading toward Obake’s hiding spot. Towards the EVO shelter, Obake knew, far behind him. Brick couldn’t make it their on his own – he’d run out of stamina before he reached the end of the block – but Obake could carry him.

A tendril of Obake’s machines snaked out of his hiding spot, stopping the two kids before they ran past. They were close enough Obake could see the relief on Brick’s stone face. “Obake,” he said, stumbling to a stop, “Stripe said he was going to get you. They were on us before we even noticed, there was nothing I could do.”

The Purple hero didn’t look relieved, he looked frightened. He’d jumped back at the sight of Obake’s machines, raised his arms up defensively. The kid, definitely too young to be playing superhero, looked more scared at the sight of the new EVO than in the firefight with Providence

Which wasn’t much of a surprise. Obake paid attention to the news; he’d seen the blurry pictures of the nanite machines that destroyed KreiTech months ago. He could put two and two together, even if the conclusion was less than ideal. Obake couldn’t remember anything of his life before becoming and EVO, but if those were the people he’d had connects to, he didn’t want to remember.

If the sight of Obake’s power brought back too many bad memories, then there was nothing he could do to fix that. He needed the Heroes to trust him, though.

The machines around Obake’s body dropped, slowly, to pool at his feet. They moved down his head, his neck, spilt down his long sleeves. Obake hated dropping his guard like this – there was no way to cover up the scars on his hands, or the ugly burn that crept up his neck into his face – but he needed the Hero to see that he was a real person too, under the mutation.

“I’ll take it from here,” Obake said. He was painfully aware of how quiet his voice sounded, but his lungs ached if he tried to raise his voice, and there was no time.

The Purple hero’s face twisted from fear into complete shock. His jaw hung open behind the visor, and he could barely keep himself standing. His throat bobbed, like he was trying to figure out what to say, but Providence was still flying by overhead, and Obake needed to get Brick out of sight fast.

“Thanks for the help,” Obake said, then his machines surged at Brick’s feet, lifting him up with ease. He turned, and his machines carried the two of them away.

* * *

Hiro didn’t know what to say to his team when they asked him, moments later, what was wrong. “You look like you’ve seen a ghost,” GoGo said. Hiro wanted to laugh, and cry.

They made it out of the fight unscathed, avoiding the remaining Providence patrol long enough to find a rooftop to hide out on. Baymax assured them that all the Providence jets were in fact leaving. “Let’s hope they got the message,” Wasabi said, then noticed that Hiro still hadn’t spoken, and asked, “Are you OK little dude? What happened?”

Hiro stared at him, trying to figure out how to explain what had happened. There was no good explanation. The others crowded him with worry, and the best Hiro could do was say, “That EVO. That was Tadashi.”

Fred had popped the food off his costume, and glanced up at Honey. “That little rock dude?” he asked. She shook her head.

“Hiro,” she said, “that wasn’t-”

“Not him,” Hiro said. “There was another one. We were running, and… and I thought it was Callaghan at first. He had my nanobots. But it wasn’t. It was Tadashi.”

None of the others had seen him. Hiro wasn’t even sure if he’d really seen him. It couldn’t have been possible. “Am I going crazy?” he asked no one in particular.

“Did you really see another EVO?” GoGo asked.

“The rock kid called him Obake,” Hiro responded. “They… knew each other.”

“’Shapeshifter’,” Honey Lemon said. She glanced around at the others. “Could it… really be?”

“We need to find out,” Wasabi said.


	3. Chapter 3

It wasn’t until the dead of winter that Hiro saw the EVO called Obake again. The whole team hunted for months, but with Providence raids becoming more common the EVOs of the city had gone further and further underground, literally. Baymax’s scanners couldn’t pick up lifeforms beneath the city streets, in the tunnels and sewer systems. Even with Big Hero 6’s high publicized stance against EVO collaring, no EVO would talk to them for long enough to learn anything. For a while it seemed like the team’s work of defending innocent EVOs had done nothing but make enemies.

“I’ve had customers complain about you,” Aunt Cass said at night, after the café had closed. She and Hiro sat together on the couch, the TV playing some historical drama neither of them were really watching. “People saying that you’re supposed to be protecting us _from_ the EVOs, not the other way around.”

It was nice, sometimes, that Aunt Cass knew what Hiro got up to. Not having to lie to her all the time was surprisingly relaxing. The only problem was her constant worry and fussing.

“Not all EVOs are monsters,” Hiro said with a scowl. He thought of Rex, who hadn’t been seen in months. Things had really gone down the drain since he’d disappeared.

“I know,” Cass said. “I just hope you know what you’re doing.”

Mochi lay in her lap, purring quietly at the warmth. There was a black kitten curled up on the floor as well, the last remaining member of a surprise litter. The kittens had been a pleasant surprise after a stressful summer, but they were all adopted out now. Hiro had just kept the one, for himself. He’d named it Dashi. He hadn’t told Aunt Cass about the nanobot EVO yet.

When they finally found Obake, Honey Lemon was the first to spot him. They’d seen the Providence ships and suited up on campus, flying across the entire city on Baymax’s back to see who needed their help. Honey’s gasp sounded through their suit comms and Wasabi frantically asked what was wrong.

“Look,” she said, and pointed to the streets below. Hiro craned his neck over Baymax’s shoulder to see a large black mass crawling through the streets. His nanobots.

“That’s him,” Hiro said. The sight of it still twisted his gut. The only time Hiro saw those nanobots anymore was in his lab data, when he worked on his microbot project for school, or in bad dreams. He couldn’t distinguish a human shape among the black blur, but he’s seen Obake – Tadashi – absolutely covered in the bots months earlier, and he was well aware of how the old tech looked when it moved.

“Those are your nanobots,” Fred stated. No one had really believed Hiro, he knew, after months of searching for a sign of those bots with nothing to show for it. It sounded like they still couldn’t believe what they were seeing now.

“I told you,” Hiro said. He signaled for Baymax to get closer to the ground. “Scan him. I need to know for sure.”

There was a brief pause as Baymax ran his scan, then, “I cannot.” Hiro’s heart sank. “The nanite field surrounding this person is throwing off my sensors.”

Hiro pounded his fist into the thick red plating on Baymax’s back, but there wasn’t time to do anything else. Providence ships loomed directly overhead, smaller vehicles gathered in force below. A fight was already underway on the street. Four EVOs dodged blaster fire from a troop of Providence agents, using crumbling chunks of dug up pavement as shields. Half the street had been turned into solid ice, and the sides of the nearby buildings were covered in what looked like a glittery slime.

“They’ve got that ray-cannon,” GoGo said as a giant device was wheeled out of a Providence van. The whole team recognized it instantly. They didn’t yet know how it worked, but they knew that EVOs hit with it were unable to fight back, leaving them vulnerable to the collars.

At Hiro’s command Baymax dived for the device, but it was Obake who stopped it from hurting the other EVOs, just in time. A thick tendril of nanobots shot out across the street, shielding them from the beam. For a moment, the person inside the mechanical swarm was visible.

Then Obake screamed in pain and Big Hero 6 jumped into action. Honey leapt from Baymax’s wing and tossed two chemical balls into the weapon, causing it to sizzle. Wasabi positioned himself between the two groups to deflect blaster shots, while Fred scattered the agents with a spray of fire. GoGo shot off like a right to join the fight, but Hiro landed on the pavement and immediately turned to run for the EVOs.

“Are you guys alright?” he asked. He kept his eyes on the EVOs, tried to ignore the nanobots spread out across the street. They’d fallen when hit by the ray-cannon, as if the nanites that controlled the bots had shorted out, but as Hiro ran up they started to move again.

“Y-yeah,” one of the EVOs said. Hiro helped her to her feet. Obake knelt on the ground several feet behind her, breathing heavily. The nanobots started covering him again, hiding him from sight. “Thank you for helping us.”

“We are glad to help,” Baymax said. Hiro hadn’t noticed the robot following him over. Obake looked up and Hiro saw his face again just before it was covered. He couldn’t breathe, but if Obake recognized Hiro or Baymax, he didn’t show any sign of it.

“I need to get you all out of here,” he said. His voice was raspy and strange but Hiro could swear he heard Tadashi in there. He reached out instinctively.

“Wait.”

Obake turned to look straight at Hiro. He could see his eyes, uncovered by the bots, shining out from the mass. “Can you hold them off,” Obake said, “and cover our escape?”

Hiro couldn’t respond at first. He stared up at the man he knew had to be his brother, somehow, still alive. The battle was raging on the street behind him and all Hiro could think was that he had so many questions, too many.

Finally, he asked, “How are you alive?”

The EVO, Obake, Tadashi, looked confused. “What?” he rasped.

“Obake,” one of the other EVOs said. “We need to go, now.” Obake looked over Hiro’s shoulder, at the Providence ships, and Hiro knew he was going to run away again.

“What happened to you?” Hiro asked hurriedly, before he lost his chance.

“What do you mean, hero-kid?” Obake said. The nanobots curled up around an injured EVO, picking him up for Obake to carry, working fast. “I’m an EVO. Same thing that happens to all of us.”

“No, I mean,” Hiro started to say, but then the words hit him. “You mean, you don’t remember?”

“The Providence ships are not retreating,” Baymxa reported. “If you wish to escape, you should do so now.”

Obake looked at Hiro oddly, like he wasn’t sure what to make of him. “I don’t know what you’re talking about, hero-kid,” he said, “but we’ve got to go. Thanks for your help.” And with one last look, Obake and the EVOs turned and fled the scene.

* * *

Obake thought about that encounter for weeks. He waited for news of the heroes, asked about sightings and reports in the newspapers. He tried to recall the kid’s face in his mind, or as much of it as he could see through the visor. The kid had looked shocked during their first meeting, a common look in a normal person meeting a dangerous EVO, but the second time around he’d seemed confused, and sad, and maybe even hopeful?

The kid knew him. That was the only explanation. He’d known Obake before he lost his memories, maybe even before his nanites had activated and he’d mutated into an EVO.

Obake had tried to find himself during those first few months. There had to be someone missing an EVO, missing a friend, missing a family member. He’d given up when all he could find were dead ends, and a suspicious connection to a terrorist.

Now it seemed like his past had found him instead.

The EVOs spent most of their days in hiding, but Obake wasn’t without resources. There were normal human contacts who could do the legwork, and public libraries he could break into at night. Obake even had a knack for repairing and rebuilding computers, which would access the internet if he could just find a wide enough wifi signal. The heroes of San Fransokyo kept a tight lid on their identities, but Big Hero 6 was still a hell of a lead for an amnesiac.

**Notes for the Chapter:**

> The kittens mentioned in this chapter, and in the first chapter, are a reference to my other fic, [Surprise Gift](http://archiveofourown.org/works/4051867). I promised a friend I'd include all previously invented kittens in this story.


	4. Chapter 4

Hiro’s microbots could practically dance, but it wasn’t enough. He’d fine-tuned the neurotransmitter until his microbots could sweep across his lab floor like leaves in the breeze, but they were still too stilted, too mechanical.

Baymax’s charging station had been moved back home and replaced with a series of clear plastic tubs, one for each prototype microbot set as Hiro developed them. They all looked the same, larger than his nanobots and white in color, manufactured at the SFIT lab instead of his aunt’s café. Each set had its own controller headset, thrown lazily over microbots as Hiro finished testing that group and moved onto the next.

The neurotransmitter now strapped to Hiro’s head belonged to his latest test group. He’d machined the batch just that week, after seeing Obake, after seeing just how complete his control over the nanobots had been.

Hiro knew now what his bots were supposed to be able to do, and this wasn’t it. He’d registered the microbots as his undergrad project because he’d realized there was still value in them – their nanobot predecessors had gotten him to school in the first place, after all – but Obake had shown him what complete technological control really looked like. The nanobots could move individually or as a single unit with seemingly no delay between controller and bot. The microbots still took at least a half-second to respond.

Hiro sunk into his desk chair and took in a deep breath before letting it out in a long sigh. He could feel the neurotransmitter headset leaving its imprint on his forehead. It was dark outside, and he’d been at this for hours with no luck. There was still another hour before Wasabi’s nightly carpool home but Hiro felt like he couldn’t think anymore.

He unbuckled the headset and the microbots, stacked into a boxy recreation of Baymax, jittered and fell to the lab floor. Hiro dropped the headset to his desk and picked his way through the mess towards the locked lab door. If anyone wanted to steal anything they’d have to risk tripping and hurting themselves, and the headsets were programmed to respond only to Hiro’s brainwave pattern.

“Where you headed?” Fred called as Hiro passed through the large shared lab. Hiro almost hadn’t noticed him, without any sort of monster costume on at all.

“Out,” Hiro said. He could hear the exhaustion in his own voice. “I need air, and a change of scenery.”

“Don’t take too long,” GoGo said from her station. She was staring hard at her project blueprints, but flashed a knowing smirk.

“I’ll be back in ten minutes,” Hiro promised. “I still gotta catch a ride with Wasabi.”

“I keep telling you,” GoGo called before he could get out the door, “you can just get a ride with me – it’d be much faster.”

Hiro turned around in the open doorway to give GoGo a look. “No,” he said.

The night air was cold but the worst of winter had passed, and Hiro’s hoodie was just enough to keep him warm. He stuck his hands in the front pocket with his phone as he walked. The Admin building was across the large courtyard lawn from the robotics labs, and it was the closest building with a vending machine. Hiro couldn’t do anything else that night until he got some food into his stomach.

During the day the courtyard was loud, filled with students all older and bigger than Hiro. At night it was completely empty, still and quiet. The lampposts over the walkway were the only source of light, and the trees cast long shadows over the lawn.

Hiro usually didn’t mind it, but tonight something felt wrong. He slowed his step and stopped under a lamppost, but when he looked around there was nothing to see. The sky was clear but moonless, the lights from all the campus buildings still bright, and leaves rustled in the trees somewhere. Except that there was no breeze.

“Hello?” Hiro called out. He thumbed his phone on. The team was on speed-dial if he needed them, and they were only a hundred yards away. “Is anyone there?”

The rustling got louder, but it sounded more like metal sliding against metal than leaves blowing in the breeze. Hiro recognized that sound. It was the sound his bots all made when they moved, and there was only one person Hiro knew of that could be causing it.

“Hey,” a voice said from the shadows. Hiro could make out the shape of him, Obake, Tadashi, just outside the circle of light from the lamppost. He looked afraid to get much closer. “I didn’t mean to startle you.”

His voice was barely audible. Hiro couldn’t tell if he was whispering or if he just couldn’t get his voice to go any louder, but Hiro was having a hard time speaking as well. Everything he’d thought of to say, since the moment he knew his brother could still be alive, had flown out of his head, leaving his brain empty and his mouth gaping.

“Why are you here?” he heard himself ask.

Obake, Tadashi, finally stepped into the light. The nanobots clacked at his feet but he wasn’t covered in them, like he had been before. This time he was huddled under what looked like three threadbare sweaters, hands jammed into his pants pockets, wearing shoes that look at least a size larger than the ones Tadashi used to wear. He wouldn’t meet Hiro’s eyes, and he looked almost afraid.

“I thought we should, probably, talk. Y’know.” It sound like he was breathing through scarred lungs, which made sense. The skin on his neck was warped slightly, and the damage branched up into his face as well. From the fire, Hiro knew. He’d put it together when he saw those scars months ago. But to see them again….

Hiro gripped the phone in his pocket tighter. Talk. That was something he used to know how to do well. With his brother. Who was back, like a miracle, from the dead. After almost a year. Hiro had mourned him and recovered and accepted. The last few months had been torture.

Hiro gulped, and just nodded.

Tadashi nodded back. He was so different and looked just the same. “So,” he said, slowly. “Your name is Hiro.”

“Y-yeah,” Hiro practically squeaked. Under normal circumstances he’d feel embarrassed.

“And these machines,” Tadashi said. The nanobots at his feet clattered, as if they knew they were being talked about. More likely they were just responding to Tadashi’s emotional state, Hiro thought. He controlled them without a neurotransmitter after all. “They’re called nanobots?”

“B-because of the nanites inside,” Hiro said. “The only way to get them to work was to piggyback off n-nanite technology.”

Tadashi glanced down at the bots. “Huh,” he said. “At first, I thought _I’d_ made them. My nanites, I mean. As some part of my mutation. I look pretty normal otherwise, so it made sense.”

He was quiet for a moment, thinking, or maybe remembering. Hiro wanted so badly for him to keep talking. Every word he spoke was an affirmation that his brother was still alive. Things would never be the same again but as long as Tadashi kept talking, Hiro could pretend.

“Then I saw those news reports when Yokai attacked. Everyone saw the machines. The, uh, nanobots. If that guy was using them then maybe _he’d_ made them.”

“Callaghan set the fire and stole them from me,” Hiro said.

Tadashi looked up and their eyes met. They stared for a beat before he spoke. “I’ve been doing a lot of research this week. There was a fire here, on campus. Two deaths. Except neither of them really died, I guess.”

Hiro practically sobbed. He could feel his eyes stinging, and fought to keep the tears back. He didn’t want to cry here, not like this.

Across the small pool of light, Tadashi looked away. “So, that guy, he steals the machines, but I also ended up with them somehow. And I’m an EVO now, but I can’t remember anything about how it happened.”

“You were trying to… to save him,” Hiro said. Tadashi considered it for a moment.

“Sounds like that didn’t do anyone any good.”

“You _died_ , Tadashi,” Hiro choked out. “I thought that Callaghan had-”

Tadashi cut him off. “ _Kid_ ,” he said, “I don’t remember _anything_. Not from that night, or anything before. It’s all gone.”

Hiro shook, slightly. Probably from the cold, or the tension running down his spine, or the way Tadashi sounded so much like Aunt Cass right then that it _hurt_.

“I-I know,” Hiro said. “I figured that… well, sometimes EVOs don’t remember things, so….”

“I’m the only one I know of,” Tadashi said. “But that’s not the point. The point is… none of the names in those news articles rang any bells.” He glanced back at Hiro again, frowning. “None of the faces in the pictures looked familiar. Well, I’d seen you, in that purple getup, but I mean….”

“You mean,” Hiro said, “that this doesn’t change anything. For you.”

“It changes some things. I know who I am now. But I’ve got people who need me.” The nanobots at Tadashi’s feet clattered and Hiro saw him as Obake again, the EVO, protector of his kind. “Providence is all over this city. _I_ can defend myself, but not everyone can.”

“So, you’re not coming home,” Hiro finished for him. He rubbed the back of his hand across his eyes.

“The streets are my home,” Tadashi said. “The EVOs are my home.” He was staring down at Hiro, his look almost one of pity, and Hiro had to look away. The shadows across the lawn seemed even darker than usual.

“I don’t know what I expected,” Hiro confessed. “I thought if I could just….”

“Kid,” Tadashi said. He made a shallow shrug. “I can’t ignore what Providence is doing because I used to be someone else.”

Hiro took a deep breath but before he could speak his phone buzzed loudly. The nanobots clattered back, responding to Tadashi’s alarm, and Hiro pulled out the phone. “It’s Honey Lemon,” he said. Tadashi wouldn’t remember that name. “My friends are wondering where I went.”

“I should go,” Tadashi said. He took half a step back.

“The brother I remember,” Hiro said, “would never turn his back on someone who needed his help. So, really, nothing’s changed, I guess.”

Tadashi stood there for a moment under the light of the lamppost. “I’ll still see you around,” he finally said, and left.

* * *

Rex panicked for a good five minutes when he didn’t recognize the bed he’d woken up on, or the cramped room he’d been sleeping in. Dr. Holiday had to explain again what was going on before he could start to remember. Breach’s time travel. Black Knight running Providence. Those collars on all the EVOs.

“Temporal jet lag,” Holiday said, as if that would explain anything. “You slept for ten straight hours. Six wanted to wake you up but I wouldn’t let him.”

“Thanks for that,” Rex muttered. He didn’t feel completely comfortable in this new renegade base. He’d hated the never-ending white Providence hallways, and the sterile smell of the lab over the Petting Zoo, but walking into this central command room felt like walking into a villain’s lair – and not in an awesome way. Plus his new room was a train car, which was cool, sure, but tiny.

The morning briefings were just as boring as ever, though. Holiday had everyone gathered by the computers to talk about Providence’s EVO collars, and Rex could already feel himself falling back to sleep.

“Why are we going over this again?” he asked, crossing his arms. “What more is there to know? I already got up close and personal yesterday, when my own brother tried to put one on me.”

“You still don’t know how these things were made” Holiday said. “The modifications Caesar made to the original collar designs.”

Rex sighed. “Who cares?” he asked. “I know how to shut them down. That’s the only thing that matters.”

“Do you remember Hiro Hamada?” Holiday asked.

“Yeah.” Rex frowned.

“Who?” Six asked.

“He’s a robots genius. We worked with him about a year ago. And these are his designs.”

Rex sat up in his chair. “You mean,” he said slowly, “that tiny twelve-year-old kid made these?”

“Your robotics genius is a twelve-year-old kid?” Six asked.

“He’s fourteen,” Holiday sighed, “and he called me, about a month after you disappeared, Rex. Caesar stole these designs, to make those collars for Black Knight. Hiro was pissed.”

Rex looked away, glaring. “Glad to hear I’m not the only one, then.”

“Why are you bringing this up now, Holiday?” Six asked. “If you wanted us to do something about it, we could have done so by now.”

“Hiro said to call him when Rex got back. He wanted to talk. And I think, if we’ve got nothing else planned, that it’s time to take a trip to San Fransokyo.”


	5. Chapter 5

It felt like Rex had been in San Fransokyo for barely five minutes when Holiday called about the EVO attack. Hiro’s team was on the move before she’d finished the first sentence. “It’s lucky you’re already in the area,” she said over the phone, after Rex had jumped into the air after Hiro and Baymax. “I don’t think the local superheroes can handle this one on their own.”

“I know what you mean,” Rex said. “I can see it from here.”

The EVO must have been at least thirty stories tall, a confused cross between a cat and a dinosaur stomping down the city streets. It turned as Rex and the others got close, and immediately began running in the opposite direction, crushing cars and cracking the pavement as it went.

“This looks like one Providence should take care of,” Rex heard Wasabi say over the team’s radio link. Hiro and Rex had caught up to it now, and circled around while the EVO flinched back, looking for a new route to escape.

“I thought you guys were all about protecting EVOs,” Rex said with a laugh.

“Not the dangerous ones!” Fred said. Rex couldn’t even see the others down on the street, but a blue blob ballooned up around the EVO’s feet and he knew that Honey Lemon was already getting to work.

“Just the ones who are innocent,” Hiro said. He zipped around on Baymax, distracting the EVO long enough for Honey and the others to pin it in place, while Rex followed close behind. They had to duck to avoid its massive paws as it began to swat the air around it.

Rex called his nanites back and his turbine wings disappeared, and he dropped onto the EVO’s head. “Either way,” he said, struggling to stay upright as the monster tried to shake him off, “with an EVO this big, Providence will be here in minutes. I’m surprised they’re not around already.”

“Spoke too soon,” Hiro said. He pointed, but before Rex could see the EVO jerked sideways and he was launched through the air. He had just enough time to call his nanites to action before he landed hard on the pavement, cracking the street around his metal boots. Fred and Wasabi jumped out of the way just in time.

“Could you try _not_ destroying our city, please?” GoGo asked over the comms. She zipped around them once and skidded to a stop just outside his landing crater.

“Fighting EVOs this big isn’t exactly easy, y’know.” Besides, the EVO itself was causing far more damage.

By now the Providence ships Hiro had seen were above the city, preparing for an assault. “Are we sticking around to see if they’ll arrest us,” Honey asked, “or running away now?”

“Running away,” Hiro said.

“Sticking around,” Rex said at the same time. The team on the street turned to stare at him, and he shrugged. “I haven’t tried to heal this guy yet,” he said. “That’s sort of my thing.”

“Well stop standing around, then,” GoGo said. She shoved him in the shoulder, hard.

“Ow, I’m going.” Honey had crusted the EVO’s feet with a few layers of her chemical blobs, so it couldn’t move to get away, and Hiro and Baymax distracted it while Rex climbed up to it. He felt the EVO’s nanites responding as he pressed his hands to its side, calling for them to revert back to normal. Slowly the nanites began to respond.

It took just a few seconds but the giant EVO crowding the street began to shrink, smaller and smaller, and morph back into something human-looking. Rex always held his breath when trying to cure somebody; this time he got to let it out in a sigh of relief. Then he was standing, at the top of a crusted mound of chemical goop, pulling the dazed stranger out of the mess.

Baymax landed just a little ways away. “It worked,” Hiro called up to him, breathless.

“You sound surprised,” Rex said.

The rest of the team rushed up to Rex to help get the man down to the street. “I’ve seen the videos,” Fred said, “but wow. That was something else.”

Rex smirked, and not just from the praise. He hadn’t cured anyone in what felt like weeks – for the rest of the world it had been months. He had depended on that ability, and his status as Providence’s ‘secret weapon’. Things must have gotten pretty desperate after he disappeared.

Hiro climbed down from Baymax’s back and stood on the street, staring up at the Providence ships in the air. They were hovering in place, no agents being sent down to clean up the mess or retrieve any EVO. “Looks like they came all this way for nothing,” Rex said. He stood next to Baymax and stared up as well. From this distance he doubted anyone up there could see him, but they’d seen the EVO disappear, so they must know he was there. He wondered if they’d try to follow him back to Holiday and Six.

“Do you think your brother might be up there?” Hiro asked. His voice sounded quiet; he’d turned his headset off and spoke to Rex from under his visor.

“I don’t know,” Rex said. Baymax wasn’t watching them, and the rest of the team was talking to the healed man. “But probably not,” he added. He couldn’t help the bitter tone that crept into his voice. “He’s working on some project for Black Knight, not out here looking for me.”

Hiro dropped his gaze. “He seemed like someone I could trust,” he said, “he helped me get back on my feet after Callaghan. I guess I didn’t really know him like I thought I did.”

“Hey,” Rex said, “I hardly know him at all, and he’s my _brother_.”

Before Rex could add anything else, Baymax spoke up. “Speaking of brothers,” he said, looking down at Hiro, “my scanners are picking up Tadashi’s EVO signature nearby.”

“Tadashi?” Rex asked. He jerked his head up and looked around. “Right now?”

Hiro stiffened at Baymax’s news and crossed his arms over his chest. He’d managed to catch Rex up on the situation before the EVO had appeared, but seemed disinclined to go into the details. Tadashi’s memory was gone, GoGo explained, and the whole ordeal had shaken Hiro up.

“He probably saw the Providence jets,” Hiro muttered. Tadashi saw his look and followed his gaze.

The thing lurking in the nearby alleyway could not be confused for a normal human at all. At first Rex thought it was a spider the size of a small car, until he realized the dark legs were in fact tendrils of nanobots, branching out from the main body where the man inside must be. Tadashi pulled away from the street as Rex watched, and the bots shifted around him like a black cloud.

“Yikes,” Rex muttered before he could stop himself. He hadn’t expected him to look so much like Yokai. “You must have thought your old nemesis was back, first time you saw him.”

Hiro attempted a chuckle but it came out more as a huff. “Actually I did,” he said. “So did everyone else; they call him Obake, underground. It’s a type of yokai. It means shapeshifter.”

“Do they really have a whole underground EVO city?” Rex asked, turning to Hiro again. “That sounds kind of crazy.”

Hiro sighed and shrugged. “It’s not like they let us in,” he said, “but that’s the gist of it. It’s why Tadashi won’t come home.” In a quieter voice, he added, “I haven’t told Aunt Cass yet.”

People started to appear on the street, wanting to see what was going on now that things were safe, and the nanobot-Tadashi swarm moved even further back into the shadows of the alley. Rex took a step forward. “You coming?” he asked Hiro.

“What?” Hiro said. “Where are you going?”

Tadashi was disappearing around a corner so Rex broke out into a run. “I’ll be back in a bit!” he called over his shoulder.

Rex chased the trailing nanobots through several alleyways before they disappeared into a sewer grate, then pinched his nose and climbed down in after them. It took his eyes a moment to adjust to the darkness, but he saw the shape of Tadashi’s nanobot swarm moving down the tunnel, and heard the metal bots scraping against the concrete. He wasn’t hard to follow.

“Hey!” Rex called out. Tadashi didn’t respond. Rex wasn’t sure if Tadashi was ignoring him, or if he couldn’t hear over the noise his bots were making, so he called out again. The nanobots didn’t slow down until almost a minute later.

When they did, Tadashi turned around abruptly. It was too dark and there were too many bots to see the man’s face, but Rex could tell he was being stared at, and he halted mid-step. “Who are you?” Tadashi asked. He didn’t sound like what Rex expected Hiro’s brother to sound like.

“I’m Rex,” Rex said. He set his hands against his hips. The smell of the sewer came over him and he immediately regretted the move. “I’m a friend. I… helped Hiro take down the Yokai last year.”

“I don’t remember you,” Tadashi said, and he turned to leave again. “Sorry.”

Rex stumbled after him. “No, we, uh, we never met. I used to work for Providence-”

“Providence?”

“Used to. Before Black Knight took over. I was the, uh. Nevermind.”

Rex had to jog to keep pace. Tadashi didn’t so much walk as slide; the nanobots covered and carried his entire body down the tunnels. It was a complex machine with a million little parts, and a man at the center who controlled them all with much more precision than Hiro or Yokai ever had. It was unnerving to watch, if Rex was being honest with himself.

“Hiro told me about you,” he added after a few moments of awkward silence. “I wanted to see if it was true.”

“If what’s true?”

Either the smell from the sewers was gone, or Rex’s nose had gotten used to it already. The tunnels Tadashi led them through didn’t seem like the usual sewer tunnels either – they were more like maintenance tunnels, traveling deeper down under the city. They seemed abandoned, but the lights were still on, and there was more light somewhere up ahead.

“If there’s really an EVO city down here,” Rex said with a grin. “It sounded really far-fetched.” They turned around another corner, into a hall that ended in an open doorway, and Rex’s expression dropped.

“There’s no city,” Tadashi said. He moved through the doorway, indicating the room. “Just us.”

The room was massive, for a secret underground bunker. There were hundreds of EVOs milling about, of all shapes and sizes, talking or eating or trying to sleep. One EVO made entirely out of fire stood in the middle of the room, cooking; on the opposite side of the room an EVO who looked like a rhinoceros looked up when Tadashi came in, and began to issue orders.

Rex and Tadashi stood on a catwalk, with practically the whole room in sight. The nanobots clicked loudly against the metal and the EVOs below them looked up, and shouted greetings to ‘Obake’. Rex stared down and muttered, “Wow.” It looked, he thought, a bit like Abysus, but smaller and underground, with Tadashi watching over the EVOs instead of Van Kleiss. “So it is true.”

“We’re a shelter, not a city,” Tadashi said. He slid back through the doorway, out of sight from the others. “It wasn’t this bad until Providence started collaring.

Rex stayed out on the catwalk. Some of the EVOs gave him curious looks but most of them ignored him, going about their business. “And Providence doesn’t know you’re down here?” he asked.

“Oh they know we’re here.” From the corner of his eye Rex could see the nanobots starting to pool at Tadashi’s feet. Slowly, layer by layer, the mechanical shell stripped away until it was just the man, standing under the dim tunnel lights. “They just don’t want to go through the trouble of digging us up yet.”

Hiro’s brother looked haggard and scarred, underneath it all. He stared at the opposite wall, avoiding Rex’s eyes, arms crossed like he was protecting himself. The nanobots weren’t lying on the floor silently either, but jittering and shaking as if from cold.

“I don’t see why you guys would pose much of a threat,” Rex said.

“No one else is resisting them,” Tadashi said. “That we’ve held out against them at all is a _big_ threat.”

“Plenty of EVOs are resisting Providence,” Rex countered.

“Like who?”

“Like me,” Rex said. He turned straight towards Tadashi. The man was older than him but it was hard to be intimidated. Rex could see Hiro in his eyes, and Caesar in the way he seemed to be hiding from everyone, and the scared confused amnesiac that Rex had once been.

Plus, Rex had to work with Six every day.

Tadashi stared at the ground. “What, are you setting up some kind of rebellion?” he asked.

“Actually, yeah,” Rex said. He felt himself getting defensive and annoyed, and he wasn’t exactly sure why.

“Did that kid set you up to this?” Tadashi asked. “To try to get me to come out of my hole?”

Ah, Rex thought. That’s why.

“ _’That kid’_ ,” he said darkly, and took a step towards Tadashi, “is your _brother_.”

Tadashi kicked at the concrete group, crossed his arms tighter across his chest. “I know,” he said softly. He still avoided Rex’s eyes and Rex felt the anger rise inside him. He took another step forward through the doorway, leaving the room full of Tadashi’s EVOs behind.

“Obviously you _don’t_ ,” Rex said, “because if you were any real brother you’d _be there_ for him.”

On the ground the nanobots jittered loudly, and Tadashi looked up with a glare. “Look, I don’t _remember_ -”

“Oh I _know_ you don’t _remember_ ,” Rex cut him off. He clenched his fists at his sides.

“And you think that means, what?” Tadashi asked. “That I should just pack up and leave behind everyone here, go sit in that kid’s house and pretend everything’s normal? Fake a relationship with a family I don’t even remember having?”

“You could try,” Rex spat. “It’s better than pretending he doesn’t even exist.”

“That’s not what I’m doing,” Tadashi said. He didn’t move, but the nanobots at his feet churned. A tendril rose to indicate the room they’d just visited. “I’m fighting, every day, to protect the people who _need_ me.”

“ _Hiro_ needs you.” Rex slumped against the opposite wall of the tunnel. He had to force himself not to raise his fists. If Hiro heard that he’d punched Tadashi, he’d probably never hear the end of it. “I know something about having a brother who doesn’t care for you.”

Rex hadn’t meant to say that, but he didn’t regret it either. That’s what it really boiled down to. It was crazy, but he saw so much of both himself and Caesar in Tadashi, and the similarities only pissed him off.

Tadashi didn’t respond at first. He still stared at the floor, crossed his arms so tight he was practically hugging himself. The nanobots were jittery, but their movements slowed, and they quieted down.

“I do care,” Tadashi finally said. He spoke slowly, trying to figure out what he wanted to say. “I spent months searching for my family. Then Hiro found me, but… as long as Providence is a threat, I can’t have a family. I can’t _be_ normal. They’re not just hunting me, they’re hunting everyone here, and Hiro’s already in danger for trying to protect us. I just….”

His voice trailed off, and Tadashi looked up. “I need to stop Providence from chasing us before I can even think about having a real life.”

“Well,” Rex said. “You’re not doing a super great job all the way down here.”

Tadashi huffed. “Thanks,” he said.

“I just mean, you could probably do more damage if you were part of a team,” Rex said. Tadashi frowned.

“I’m not joining Big Hero 6, if that’s what you mean,” he said.

“No, I mean _my_ team,” Rex said. “I haven’t seen you in action, sure, but if you’re half of what Yokai was, I bet we could use you.”

“You mean your ‘rebellion’?” Tadashi asked skeptically. “I don’t think I’d trust any rebellion run by a teenager.”

“I’m not running it,” Rex said with a smirk. “I’m just the secret weapon.”

Tadashi raised an eyebrow at that, but didn’t question it. “I can’t leave San Fransokyo,” he said instead. “Not while Hiro’s here, and not while the EVOs here need me.”

“Now you’re just finding excuses to say no to me,” Rex said, but he sighed. “Ok, what if I just… call you for help?”

“What?”

“You want to stop Providence hurting innocent people, right? If we find a way to stop them before they do something bad, and we need your help, can I call you?”

Tadashi considered that for a moment. Finally, he said, “I don’t have a phone.”

Rex let out a low groan. “And if I get you a phone?”

“Then… sure.” The nanobots began to clack against each other again. Tadashi seemed to be hiding a ghost of a smile. “I’ll help you put a wrench in any of Providence’s plans.”


End file.
